Minimum - resources MBDCG

RaulBSP · Post by **RaulBSP** » Thu Mar 01, 2007 10:07 pm

Hi!

I´m trying to make MBDCG holograms without TMG. Instead I used some glycerin and a NaOH + Boric Acid buffer to keep the high pH.

This is my first viewable hologram I've ever done. It is very dim (there are 10 cents coins), I suspect

due to the alcohol poor quality. (ethyl alcohol, 90%). Initially, when the alcohol is still wet, hologram is very bright and golden color. Then, as it dries, it becomes like in the photo.

I didn't use pH-mether neither pH-strip indicator. Instead I used the same methylene blue as indicator. Adding a drop of MB to the emulsion, if pH is low, the color is dirty orange, adding some buffer, the ph is rised until the emulsion color turns to clean blue.

Hologram was shot using a 100 mw DVD laser diode (50 mw useful for holography), without temperature control.

Martin · Post by **Martin** » Fri Mar 02, 2007 4:19 am

RaulBSP wrote:Hi!

I´m trying to make MBDCG holograms without TMG. Instead I used some glycerin and a NaOH + Boric Acid buffer to keep the high pH.
This is my first viewable hologram I've ever done. It is very dim (there are 10 cents coins), I suspect
due to the alcohol poor quality. (ethyl alcohol, 90%). Initially, when the alcohol is still wet, hologram is very bright and golden color. Then, as it dries, it becomes like in the photo.
I didn't use pH-mether neither pH-strip indicator. Instead I used the same methylene blue as indicator. Adding a drop of MB to the emulsion, if pH is low, the color is dirty orange, adding some buffer, the ph is rised until the emulsion color turns to clean blue.
Hologram was shot using a 100 mw DVD laser diode (50 mw useful for holography), without temperature control.

That's amazing, very interesting, congratulations!

Sergio · Post by **Sergio** » Fri Mar 02, 2007 4:15 pm

Impressive. The buffer control is a good idea. Maybe you could sandwish the film between two plates with a cover and with alcohol inside just to photograph it to us...

I think if you find elsewhere any pure alcohol you will complete the job, the "transmission" images are great.

Raul have you used a glass etalon (~5 mm) to verify the laser stability?

RaulBSP · Post by **RaulBSP** » Fri Mar 02, 2007 4:58 pm

I'm trying to find a better alcohol.

I use a piece of glass for checking the interference pattern. It can be seen

even using a thick block of glass (5 cm) that gives a 10 cm coherence length, I think.

I used to ajust laser diode current until pattern appears, then I give it stay

until stabilizes.

Joe Farina · Post by **Joe Farina** » Fri Mar 02, 2007 5:45 pm

Nice work. There is a 99.8% grade of isopropyl alcohol sold by Techspray. This is commonly available from many electronics suppliers, and is used for cleaning purposes. Some further details can be found at http://www.techspray.com

Ed Wesly · Post by **Ed Wesly** » Fri Mar 02, 2007 5:48 pm

I am totally impressed with the ingenuity and use of the barest amount of resources! Congratulations!

glajciorz · Post by **glajciorz** » Fri Mar 02, 2007 6:42 pm

Impressive, minimalistic and simple

Welcome holographer

Raul, what was the exposure time, beam diameter (is the ring around the coins a trace of a beam - I'm curious about sensitivity) ?

Did you use raw or colimated beam ?

How long did the plate stayed unexposed (dark reaction) ?

What was the swelling bath temperature ?

As for your ethanol - you could dry it by boiling (with recondensing fumes) with some phosphorus pentoxide or freshly preheated calcium oxide.

I hope it helps.

greetings

Adam

Joe Farina · Post by **Joe Farina** » Fri Mar 02, 2007 7:16 pm

glajciorz wrote:freshly preheated calcium oxide

That's a good point. This was discussed a long time ago on this forum, and as I recall, it does work to a certain extent (according to what was posted). How dry the alcohol can get, I don't know. I have some Drierite, which is a common type of material. Accoding to my Materials Handbook by Brady/Clauser, Drierite is calcium sulfate, the same thing as gypsum, which we find in wallboard or drywall. Gypsum is found naturally in the form of alabaster stone. If one wanted to keep the "minimum resources" attitude, perhaps a piece of alabaster could be broken into small fragments, thoroughly roasted, then placed in the 90% alcohol to soak up the excess water. But it would be a lot easier to find an electronics supply store that stocks the Techspray 99.8% isopropyl, which is cheaply available in one-pint containers.

dave battin · Post by **dave battin** » Fri Mar 02, 2007 9:08 pm

RaulBSP wrote:I'm trying to find a better alcohol..

most drug stores in the states can get the 99%ALC. with a day notice.

Could the pharmacy's in cuba do the same ???

RaulBSP · Post by **RaulBSP** » Fri Mar 02, 2007 10:26 pm

dave battin wrote:most drug stores in the states can get the 99%ALC. with a day notice.
Could the pharmacy's in cuba do the same ???

Things are not the same in Cuba as in the States. Here is difficult to find high quality ethanol even in a pharmacy.

Therefore Techspray 99.8% isopropyl alcohol may be a good dream.